Rotary pivoted hammer



May 14, 1940. T. H. PoEsE ROTARY PIVOTED HAMMER Filed Aug. 22, 1938f///ffffffflffffffJ Patented `May 14, 1940 UNITED STATES PATENT OFFICE 6Claims.

This invention 'relates to certain new and usefulimprovements in rotarypivoted hammers, the `peculiarities of which will be hereinafter fullyVdescribed and claimed.

. More specifically, this invention relates-to such lhammers made of-plate steel and having their outer -ends formed in folds orcorrugations extending backward from the front edge in the plane ofrotation, so as vto make the front opera'tve edge thicker than therelatively thinshank portion.

The objects of my invention are to provide means first, for lessenng theresistance of the shanks in passing through the material being reducedand thus to operate the machine on correspondingly less power; second,to increase production and efficiency of the machine; third, to

reduce the loss of eiciency due to wear of thel operating edge of thehammer; fourth, for causing such wear so to change the operating edge ofthe vhammer so that -it is substantially selfsharpening; fifth, forspacing the hammers on their pivot rods; and other features ofconstruction hereinafter-described and claimed.

In the accompanying drawing in which like reference numerals indicatecorresponding parts.

Fig. 1 represents a vertical sectional elevation of a machineexemplifying my invention;

Fig. 2, an enlarged dat face View of one of -my hammers Vand portions ofadjacent parts on which it is mounted, the main shaft and pivot rodbeing in section in the plane of rotation;

Fig. 3, anY edge View of said hammer and parts lshown in Fig. 2, thedisks being in section;

Fig. 3a,a detail of the inner-end of my hammer; Aand Fig. A'Laperspective view of the operative edge of saidhammer indicating thechange produc-ed by Wear. -f

Referring to the .drawing the numeral l indicates the casing of agrinder in which is mountvedamain shaft 2 of a rotor on which are mount-`ed disks 3 spaced apart by collars 4. In these disks are aset ofconcentric openings in which aremounted rods 5 on which are pivoted theinner lend of the Shanks E of plate steel hammers Vwhich `extend outwardtill their outer ends are in close proximity to a perforated screen 'lthrough which the material being ground is discharged when it issuiiiciently reduced to pass through the perforations.

'A portion of the outer end of this hammer is increased in the thicknessof its operating edge over the thickness of the ShankB, by being; formedinifolds or corrugations, the inclined portionsf (Cl. 83-11) -of whichyform 90 angles ror .less with each other as shown in Fig. 3. Themeeting edges forming ridges S of said folds are thus disposedalternately on opposite sides of the plane of the shank Vii so that thethickness of lthe operativeedge is 5 ysuchnthickness of the operativeedge is substantially ve times the thickness of the shank. The outer endIS of said hammer is foldedapproximately straight across the .width ofthe Vhammer 1'5 face so that it rotates in close proximity to theperforated screen and facilitates the discharge-of the nely groundmaterial through the perforations. As shownin Fig. 3, this corrugatedouter end of the hammers forms .a zigzag operative 20 edge, and saidhammers as mounted in the machine, are substantially parallel to eachother in their shanks and zigzag operative edges.

The material entering the casing of the machine is subject to impact bythe operative zigzag edges of the hammers until suiciently reduced topass through the screen. The partly reduced material that passes insidethe hammer circle of the outer ends l0 of said hammeraoiers littleresistance to the rotation of the thin Shanks 30 lwhich pass throughsaid material without Yas much rotative impulse thereon as would be thecase if the Shanks Were as thickA at the operative edges as in the usualform of straight barpivoted hammers. 'I'hus the rotation of the rotor in35 grinding with this form of hammer, requires less vpower to operate itthan when thevusual form of hammers is used. Tests by ammeter'of thisform of hammer shown and described-above, indicate that the powerrequired is lessened by 10% as Q40 compared with the usualform ofstraight bar hammers in which'thethick shanks act .with a rotativeaction upon the material being reduced. Also with my form of hammer, thematerial is not carried around with the hammers. as much 45 as in theusual form, and therefore'the impact of the hammers upon. the relativelyslower movement of the material, causes a greater'impact and increasedefiiciency of reduction. Tests have shown that the output ofthe Vgroundmaterial 5,0 is increased 25% by the use of my form of hammer abovedescribed.

Thus not only the lesser power required, :but the increased productionobtained by :the use of my form of hammer, are of :advantage and JI5 5increases the usefulness of the machine operated lwith hammers abovedescribed.

The thickness of plate steel used for making my form of hammers variesaccording to the material on which they are employed. Thus for )grindingsoft material such as oats, barley, mill feed screenings, scrap leather,and such material, the preferred thickness of the plate varies from 11gto 1/8. Saw plate steel is preferred.

For grinding corn cobs, shelledv corn, ear corn, and such material thepreferred plate thickness is l@ to 1/4 inch.

The thinner plate steel is preferred for grinding brous roots such asdarris that is pulverized to form bug dust. Other roots such as tombofrom Brazil, Cuba root from Venezuela, and a flower from Japan andintermediate islands to Java which is like a wild diasy and hard togrind is made into Pyrethrum powder by hammers of my construction.

Various chemicals and drug products such as salts and crystals whichrequire impact more than cutting action, are reduced by hammers having aplate thickness of 1/8 to 1/4 inch. For instance, tartaric crystals formaking cream of tartar are reduced by plate hammers of preferredthickness of 1A inch. l

The speed of rotation varies with the diameter of the hammer circle.Thus rotors having a 40" hammer circle are preferably run at 1800 R. P.M.; a 28 hammer circle, 3600 R.. P. M.; iand an 8" hammer circle at9,000 R. P. M. in 'machines used in laboratories.

In grinding and pulverizing Egyptian rock, and other igneous or traprock material, in which 'heavy impact blows are required, the greaterthickness of plate is preferred in my hammers.

These hammers with their zigzag corrugated operative edges, arepreferably formed by dies and at relatively low cost. The operativezigzag edges may be tempered if so desired.

The wear on said zigzag edge is indicated by dotted lines in Fig. 2 asbeing greatest in the inclined folds 8 connecting the meeting edges 9which latter appeared to resist the wear more than the inclined portions8. The extreme fold IU Wears its outer corners rounding as indicated inFig. 4 and forms one side of the extreme tooth 9. Thus the resultingeffect of wear upon the operating edge will form a series of teeth atthe meeting points 9 which are caused by hollows or recesses produced bywear as indicated in the perspective view Fig. 4. The toothed edge thusformed is practically as eicient as the original zigzag edge, and thehammer is thus substantially self sharpening.

On the inner end of my hammer, I provide integral means for spacing therelatively thin shank between the disks 3 by producing a thickened innerend by a fold or single corrugation l0 (Fig. 3a) similar to those at the`outer end; or by turning the corners 6' of the inner end inrespectively opposite directions as indicated in Figs. 2 and 3 so thatthey ll the respective space between the adjacent disks and space thehammers uniform distance apart as indicated in Fig. 3. The oppositelyfolded corners of the inner end present beveled edges and avoid hangingup on the edge of the disk when the hammers are disposed in such aposition that the said corners engage the periphery of the adjacent diskas when the rotor is at rest or about to stop or start.

It will be noted that the two inner corners of the bar when turnedoutward are disposed substantially at right angles to the plane of theshank and their points formed by inclined edges, are adapted to bear onthe respectively adjacent disks and thereby centrally dispose the Shanksbetween said disks. When the rods are so near the periphery that theseoppositely turned corners rnay engage the periphery of the disks exceptwhen the centrifugal force causes the shank to be radially disposed, theinclined edges of the triangular projections, if they should engage theperiphery of adjacent disks,.will make` only a sliding engagementtherewith and thuswill not obstruct the hammer fromtakingit's radialposition under rotation. These projecting portions near the outer andinner ends make the operative thickness Aof the ends substantially thesame.

Thus my plate bar hammer is bent outward laterally at and near bothends. Also when the transverse corrugations extend from the front to therear edge as shown in the drawing, the hammer can be reversed upon itspivot rod so as to present the rear edge as a new front operative edgeand thus extend the life of the hammer.

These alternately and oppositely` inclined folds of the corrugations atthe outward end of the bar, form meeting edges or ridges of thecorrugations slightly rounded as shown in the drawing, of the operativeedge, to facilitate forming the same by dies.

The portions 8 connecting the ridges of the corrugations may be straightas shown or otherwise formed. f

I do not limit myself uto the exact construction herein shown anddescribed except by the appended claims. l

Having thus fully described my invention, what I claim as new and desireto secure by Letters Patent, is:

l. A rotary pivoted hammer-,comprising a fiat plate bar forming a shankadapted for pivotal mounting at its inner end and having at its outerend corrugations extending transversely backward from its front edge andlaterally from the plane of the shank so arranged in transverse foldsthat adjacent ridges lie alternately on one side and then the otherofthe radial plane of the length and width of the bar, forming a zigzagoperative front edge.

2. A rotary pivoted hammer comprising a fiat plate bar forming arelatively thin shank com pared to its width and having alternatelyinclined folds at its outer end forming ridges offset laterally andaltcrnatelyfromboth flat faces of the shank, and connecting `the frontand'rear edges of the bar transversely to the length of the hammer, andAso arranged that adjacent ridges lie alternately on one side and thenthe other of the radial plane of the length and width of the bar, toincrease the effective thickness of the operative edges over thethickness of said shank.

3, A rotary pivoted hammer consisting of a at bar relatively thincompared to its width and forming a ilat, thin shank, and havingtransverse folds forming corrugations at its outer end and thusincreasing the effective thickness of its operative edge whilemaintaining the thinness of said bar throughout its length, saidtransverse folds being so arranged that adjacent ridges lie alternatelyone one side and then the other of the radial plane of the length andwidth of the bar. i

4. A rotary pivoted hammer of plate `steel bent into transverse foldsand ridges at and near its outer end, said transverse folds being soarranged that adjacent ridges lie Valternately on one side u and thenthe other of the radial plane of the length and Width of the hammer, andsaid ridges being oiset from opposite faces of the hammer and adapted toform teeth in the operative edge when the wear under usage makesconc-ave recesses in the connecting folds.

5. A rotary pivoted hammer of plate steel characterized by havingoifset, laterally projecting portions near each end, said portions nearthe outer end lying in transverse folds that are so arranged thatadjacent ridges lie alternately on one side and then the other of theradial plane of the length and Width of the hammer, and the portions atthe inner end projecting sufficiently to make the said endssubstantially the same operative thickness.

6. A rotary grinding machine comprising spaced disks on a rotary shaftand having a set of pivot rods passing through said disks adjacent theirperiphery, in combination with plate steel rectangular bar hammerspivoted on said rods and characterized by having their two inner cornersturned outward substantially at right angles to the plane of the shankforming triangular projections having edges inclined to the radial planeparallel to the disks, of the length and widthof the shank and formingoffset points having inclined edges meeting from opposite directionsadapted to bear on an adjacent disk to position in a deiinite operativeplane the shank of the respective hammer, and the slanting edges of saidprojections being capable of sliding engagement with the periphery ofthe adjacent disk tor.

THEODORE I-I. POESE.

